Pregnancy is a normal and healthy state that many women aspire to at some point in their lives. However, pregnancy can make women more susceptible to certain infections. Pregnancy may also make these infections more severe. Even mild infections can lead to serious illness in pregnant women.

Some infections that occur during pregnancy primarily pose a risk to the mother. Other infections can be transmitted to the baby through the placenta or during birth. When this occurs, the baby is at risk for health complications as well.

Some infections that develop during pregnancy can lead to miscarriage, preterm labor, or birth defects. They may even be life-threatening for the mother. To complicate matters, the medications used to treat infections can cause serious side effects, especially for the baby. It’s important to try to prevent infections in pregnancy to minimize risks to both mother and baby.

Why pregnant women are more susceptible to infection

Pregnancy affects every system in your body. Changes in hormone levels and immune system function can make you more vulnerable to infections and serious complications. Labor and delivery are especially susceptible times for both you and your baby.

Changes in immunity

The immune system defends the body against harmful invaders. It fights against everything from bacteria to cancer cells to transplanted organs. A complex collection of players works together to identify and eliminate foreign intruders.

During pregnancy, your immune system changes so that it can protect both you and your baby from disease. Different parts of your immune system are enhanced while others are suppressed. This creates a balance that can prevent infection in the baby without compromising the health of the mother.

These changes also help protect your baby from your body’s defenses. In theory, your body should reject the baby as “foreign,” but it doesn’t. Similar to an organ transplant, your body sees your baby as part “self” and part “foreign.” This keeps your immune system from attacking the baby.

Despite these protective mechanisms, you’re more prone to infections that don’t normally cause illness. During pregnancy, your immune system has to work harder since it’s supporting two. This makes you susceptible to certain infections.

Changes in body systems

Aside from changes in immune function, hormonal changes can also increase your risk for infection. These fluctuations in hormone levels often affect the urinary tract, which is made up of:

  • the kidneys, which are organs that produce urine
  • ureters, which are tubes that carry urine from the kidneys to the bladder
  • bladder, which is where urine is stored
  • urethra, which is a tube that transports urine out of the body

As the uterus expands during pregnancy, it puts more pressure on the ureters. Meanwhile, the body increases the production of a hormone called progesterone, which relaxes the ureter and bladder muscles. As a result, urine may stay in the bladder too long. This increases your risk of developing a urinary tract infection. Hormonal changes also make you more susceptible to a type of yeast infection known as candidiasis. Higher levels of estrogen in the reproductive tract predispose you to yeast infections.

Additionally, changes in the amount of fluid in the lungs can raise your risk for lung infections, such as pneumonia. Your lungs contain more fluid during pregnancy, and the increased amount of fluid puts more pressure on the lungs and abdomen. This makes it harder for your body to clear this fluid, causing the fluid to build up in the lungs. The extra fluid stimulates bacterial growth and hinders your body’s ability to resist infection.

Risks for mother and baby

Risks for mother

Some infections that occur during pregnancy pose problems primarily for the mother. These include urinary tract infections, vaginitis, and postpartum infection.

Risks for baby

Other infections are particularly troublesome for the baby. For example, cytomegalovirus, toxoplasmosis, and parvovirus can all be transmitted from mother to baby. If this happens, it may have serious consequences.

No effective treatment yet exists for a cytomegalovirus infection that’s present at birth. Antibiotics are available that may be able to treat toxoplasmosis successfully. Although there are no antibiotics for parvovirus, the infection can be treated with intrauterine blood transfusions.

Risks for both mother and baby

Some infections are particularly harmful to both mother and baby. These include:

Antibiotics are effective against syphilis and listeria in the mother and baby, if the infection is diagnosed promptly. Though there are no antibiotics for viral hepatitis, vaccines are now available to help prevent hepatitis A and B infections.

HIV infection

An HIV infection during pregnancy is a serious and potentially life-threatening problem. However, new multidrug combinations now significantly prolong life span and improve the quality of life for people with HIV. Along with cesarean delivery before the onset of labor, these drug therapies have been remarkably effective in reducing the rate of transmission of HIV infection from pregnant women to their babies.

Group B streptococcus

Doctors test every woman at the end of pregnancy for GBS. This infection is caused by a common bacterium known as group B streptococcus. According to the Centers for Disease Control and Prevention, about 1 in 4 women carry a GBS infection. This infection is most often transmitted during vaginal deliveries, as the bacterium may be present in the mother’s vagina or rectum. In pregnant women, the infection can cause internal inflammation and also stillbirth. Newborns infected with GBS can develop serious and potentially life-threatening infections. These include sepsis, pneumonia, and meningitis. When left untreated, such infections can cause birth defects in the baby, including hearing or vision loss, learning disabilities, and chronic mental impairments.

The importance of knowledge and ongoing care

The relationship between you and your doctor is vital during your pregnancy. Knowing about the increased risk of infection during pregnancy and the potential harm to you and your baby can help you prevent transmission. Being aware of the different types of infection that could arise also allows you to recognize the symptoms. If you become ill, receiving a prompt diagnosis and effective treatment can often prevent complications. Make sure to talk to your doctor about any concerns or questions you have during pregnancy.

How to prevent infections in pregnancy

Infections in pregnancy are preventable. Taking small, everyday precautions can go a long way in reducing possible harm to you and your baby. To help prevent infections during your pregnancy, you should:

  • Regularly wash your hands with soap and water. This is especially important after using the bathroom, preparing raw meat and vegetables, and playing with children.
  • Cook meats until they are well-done. Never eat undercooked meats, such as hot dogs and deli meats, unless they are re-cooked until hot.
  • Don’t consume unpasteurized, or raw, dairy products.
  • Don’t share eating utensils, cups, and food with other people.
  • Avoid changing cat litter and stay away from wild or pet rodents.
  • Practice safe sex and get tested for sexually transmitted infections.
  • Make sure your vaccinations are up-to-date.

Schedule an appointment with your doctor right away if you’re sick or believe you’ve been exposed to a contagious disease. The sooner an infection is diagnosed and treated, the better the outcome for you and your baby.